Vehicle seat occupant status classification using multiple sensors

• US 7,024,294 B2
• Filed: 09/02/2003
• Issued: 04/04/2006
• Est. Priority Date: 09/04/2002
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Sullivan, Stuart S., Patterson, James F., Murphy, Morgan D., Gray, Charles A.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Marc, McDieunel
• Application Number:
  US10/653,698
• Publication Number:
  US 20040080425A1
• Time in Patent Office: 945 Days
• Field of Search: 701/45, 340/420, 340/667, 340/571, 340/825.75, 280/735, 180/273, 738/623.91, 702/43
• US Class Current: 701/45
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0155 sensing belt tension

Abstract

A multiple sensor, vehicle seat occupant status determination system uses dynamic variations in occupant responsive sensor output due to accelerations of the vehicle seat to discriminate via a statistical method between sensors that are failed and those that are operating correctly and eliminates the contribution of signals detected as not valid from the status determination. If and only if the maximum and minimum sampled signal values of at least one of the received signals span upper and lower control reference values derived from the sampled signal values, a variance value for each of the signals is derived; and one or both of the greatest two or the smallest two variance values are checked against a relative size factor to detect an outlier signal value. If an outlier signal value is detected more than a predetermined number of consecutive times, the status classification is performed without signal values from the outlier sensor.

Claims

1. A method of determining a status classification of a vehicle seat occupant comprising the steps:

receiving signals for a predetermined time from a plurality of sensors responsive to a physical characteristic of an occupant at diverse locations on a vehicle seat apparatus;

deriving upper and lower control reference values from the received signals;

deriving maximum and minimum sampled values of each of the received signals during the predetermined time and comparing the derived maximum and minimum sampled values for each of the received signals to the upper and lower control reference values;

if and only if the maximum and minimum sampled values of at least one of the received signals span the upper and lower control reference values for that received signal, performing the following steps (a) through (d);

(a) deriving a variance value for each of the received signals for the predetermined time,

(b) identifying two of the received signals having derived variance values that are a selected one of the largest and the smallest of the variance values of the received signals,

(c) comparing a ratio of the derived variance values of the selected two of the identified signals with a first relative size factor,

(d) if the ratio exceeds the relative size factor, marking as an outlier one of the two identified received signal having a variance value that is furthest in magnitude from the remainder of the variance values; and

determining the status classification from the received signals in a predetermined classification process, but without the use of any received signal marked as an outlier more than a predetermined number of consecutive times.

2. Apparatus for determining a status classification of a vehicle seat occupant comprising:

means for receiving signals for a predetermined time from a plurality of sensors responsive to a physical characteristic of an occupant at diverse locations on a vehicle seat apparatus;

means for deriving maximum and minimum sampled values of each of the received signals during the predetermined time and comparing the derived maximum and minimum sampled values for each of the received signals to defined upper and lower control limits;

means for performing the following functions (a) through (d) if and only if the maximum and minimum sampled values of at least one of the received signals spans the upper and lower control limits for that received signal;

(a) deriving a variance value for each of the received signals for the predetermined time,

(b) identifying two of the received signals having derived variance values that are a selected one of larger and smaller than the variance values of the remaining received signals,

(c) comparing a ratio of the derived variance values of the two of the identified signals with a first relative size factor,

(d) if the ratio exceeds the relative size factor, marking as an outlier one of the two identified received signal having a variance value that is furthest in magnitude from the remainder of the variance values; and

means for determining the status classification from the received signals in a predetermined classification process, but without the use of any received signal marked as an outlier more than a predetermined number of consecutive times.